Lightning protection for avionics systems is typically provided by protection circuits that use transorbs or similar clamping devices. These protection circuits are typically designed to dissipate large amounts of energy but often at the expense of device precision. For example, the operating voltage of most transorbs vary significantly from part to part, as well as with operating current and temperature. Therefore, fitting these protection circuits in avionics systems is technologically challenging and economically prohibitive because the protection circuits must be custom-designed for each system due to the variability in component characteristics and performance.
Furthermore, transorbs cannot be readily tested once they are embedded and in use in a lightning protection circuit. Consequently, a load coupled to the circuit may remain unprotected, because it is not possible to know whether a transorb has failed. Stated otherwise and more generally, in typical lightning protection circuits that use transorbs, it is challenging to ascertain whether a load is actually being protected because it is difficult to determine whether the transorbs are operational when the circuits are powered on.